The present invention relates to a particle accelerator comprising at least two accelerating tubes having a high-voltage side and a low-voltage side, with a channel comprising provisions for the injection of a gas therein being provided between the high-voltage sides of said accelerating tubes, and at least one vacuum pump connected to said channel.
A particle accelerator of this type is generally known. In particular a particle accelerator is known wherein a gas is injected into the charge-exchange channel (=CEC), which gas is pumped from the CEC by the vacuum pump after having interacted with a beam consisting of one or more types of charged or neutral particles. Said gas must be prevented from finding its way into the accelerating tubes as much as possible, because this leads to undesirable charge-exchange processes in said accelerating tubes, resulting in a reduced output and quality of the particle accelerator. The vacuum pump is supplied with the necessary power by a generator, for example, which is coupled with a motor via a driving mechanism, which for example comprises an electrically insulating driving shaft or driving belt. Said insulating driving mechanism electrically separates the vacuum pump and the generator present in the terminal, which are on high voltage, from a motor on a much lower voltage, namely on earth potential.
The drawback of the known particle accelerator is that the pump present in the terminal lacks in accessibility. Frequently the encasing housing the terminal and the accelerating tubes, which is usually made of metal, must be opened in order to carry out maintenance work, and the necessary electric screening facilities must be dismounted, and be mounted again after said maintenance work on the vacuum pump has been completed. This makes the required regular maintenance work on the vacuum pump(s) time-consuming and costly and, moreover, reduces the effective output of the known particle accelerator.
Another drawback of the known particle accelerator is the fact that a generator and a motor as well as an insulated driving mechanism mounted therebetween are required to provide the necessary electric power for the vacuum pump. Said parts require maintenance at an awkward place, and they are vulnerable to high-voltage breakdowns, which inevitably occur in particle accelerators of this type.